博客链接:使用 kubeadm 创建高可用 Kubernetes 及外部 etcd 集群
前言
Kubernetes 的官方中文文档内容全面,表达清晰,有大量示例和解析
无论任何情况下都推荐先花几个小时通读官方文档,来了解配置过程中的可选项,以及可能会遇到哪些问题
本文基于官方文档中 入门 - 生产环境 一章来整理摆设流程
Kubernetes 文档 | Kubernetes
架构
- OS: Debian 12
- CGroup Driver: systemd
- Container Runtime: containerd
- CNI: Calico
- Kubernetes: v1.32.0
注意
全部节点服务器都需要关闭 swap
- Other
- 说明
- 该服务器运行 K8S 外部应用,包括 Nginx、Nexus 等
- 该服务器运行的全部业务通过 docker-compose 管理
- 与 K8S 自身配置相干的步调说明中的“全部节点”不包括该服务器
- Server
- Network: 192.168.1.100 2E:7E:86:3A:A5:20
- Port:
- 8443/tcp: 向集群提供 Kubernetes APIServer 负载平衡
- Etcd
- Server
- Network
- Etcd-01: 192.168.1.101 2E:7E:86:3A:A5:21
- Etcd-02: 192.168.1.102 2E:7E:86:3A:A5:22
- Etcd-03: 192.168.1.103 2E:7E:86:3A:A5:23
- Port:
- 2379/tcp: etcd HTTP API
- 2380/tcp: etcd peer 通讯
- Master
- Server
- Network
- Master-01: 192.168.1.104 2E:7E:86:3A:A5:24
- Master-02: 192.168.1.105 2E:7E:86:3A:A5:25
- Master-03: 192.168.1.106 2E:7E:86:3A:A5:26
- Port:
- 179/tcp: Calico BGP
- 6443/tcp: Kubernetes APIServer
- 10250/tcp: kubelet API
- Node
- Server
- Network
- Node-01: 192.168.1.107 2E:7E:86:3A:A5:27
- Node-02: 192.168.1.108 2E:7E:86:3A:A5:28
- Node-03: 192.168.1.109 2E:7E:86:3A:A5:29
- Port:
- 179/tcp: Calico BGP
- 10250/tcp: kubelet API
配置基础环境
说明
全部节点
- apt update
- apt upgrade
- apt install curl apt-transport-https ca-certificates gnupg2 software-properties-common vim
- curl -fsSL https://mirrors.ustc.edu.cn/kubernetes/core:/stable:/v1.32/deb/Release.key | gpg --dearmor -o /etc/apt/keyrings/kubernetes-apt-keyring.gpg
- chmod 644 /etc/apt/keyrings/kubernetes-apt-keyring.gpg
- echo "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] https://mirrors.ustc.edu.cn/kubernetes/core:/stable:/v1.32/deb/ /" | tee /etc/apt/sources.list.d/kubernetes.list
- curl -fsSL https://mirrors.ustc.edu.cn/docker-ce/linux/debian/gpg -o /etc/apt/keyrings/docker.asc
- chmod a+r /etc/apt/keyrings/docker.asc
- echo "deb [signed-by=/etc/apt/keyrings/docker.asc] https://mirrors.ustc.edu.cn/docker-ce/linux/debian bookworm stable" | tee /etc/apt/sources.list.d/docker.list
- apt update
- apt install containerd.io
- mkdir -p /etc/containerd
- containerd config default | tee /etc/containerd/config.toml
- systemctl restart containerd
- apt install kubelet kubeadm kubectl
- apt-mark hold kubelet kubeadm kubectl
复制代码 开启 ipv4 转发
编辑 /etc/sysctl.conf,找到下方配置并取消注释执行 sysctl -p 应用配置
创建 crictl 配置- cat << EOF > /etc/crictl.yaml
- runtime-endpoint: unix:///run/containerd/containerd.sock
- image-endpoint: unix:///run/containerd/containerd.sock
- timeout: 10
- debug: false
- EOF
复制代码 如果需要通过代理服务器访问容器仓库,需要为 containerd 配置代理服务- mkdir -p /etc/systemd/system/containerd.service.d
- cat << EOF > /etc/systemd/system/containerd.service.d/http-proxy.conf
- [Service]
- Environment="HTTP_PROXY=http://username:password@proxy-server-ip:port"
- Environment="HTTPS_PROXY=http://username:password@proxy-server-ip:port"
- Environment="NO_PROXY=localhost,127.0.0.0/8,10.0.0.0/8,172.16.0.0/12,192.168.0.0/16"
- EOF
- systemctl daemon-reload
- systemctl restart containerd.service
复制代码 已知问题
使用 systemd 作为 CGroup Driver 且使用 containerd 作为 CRI 运行时
需要修改 /etc/containerd/config.toml,添加如下配置
相干文章:配置 systemd cgroup 驱动 | Kubernetes- [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
- ...
- [plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc.options]
- SystemdCgroup = true
复制代码 执行 systemctl restart containerd
或参照另一篇文章的办理方案
相干文章:Why does etcd fail with Debian/bullseye kernel? - General Discussions - Discuss Kubernetes- cat /etc/default/grub
- # Source:
- # GRUB_CMDLINE_LINUX_DEFAULT="quiet"
- # Modify:
- GRUB_CMDLINE_LINUX_DEFAULT="quiet systemd.unified_cgroup_hierarchy=0"
复制代码 执行 update-grub 并重启
配置 etcd 节点
将 kubelet 配置为 etcd 的服务管理器
说明
全部 etcd 节点
- apt update
- apt install etcd-client
- mkdir -p /etc/systemd/system/kubelet.service.d
- cat << EOF > /etc/systemd/system/kubelet.service.d/kubelet.conf
- apiVersion: kubelet.config.k8s.io/v1beta1
- kind: KubeletConfiguration
- authentication:
- anonymous:
- enabled: false
- webhook:
- enabled: false
- authorization:
- mode: AlwaysAllow
- cgroupDriver: systemd
- address: 127.0.0.1
- containerRuntimeEndpoint: unix:///var/run/containerd/containerd.sock
- staticPodPath: /etc/kubernetes/manifests
- EOF
- cat << EOF > /etc/systemd/system/kubelet.service.d/20-etcd-service-manager.conf
- [Service]
- Environment="KUBELET_CONFIG_ARGS=--config=/etc/systemd/system/kubelet.service.d/kubelet.conf"
- ExecStart=
- ExecStart=/usr/bin/kubelet $KUBELET_CONFIG_ARGS
- Restart=always
- EOF
- systemctl daemon-reload
- systemctl restart kubelet
复制代码 为 kubeadm 创建配置文件
说明
Etcd-01 节点,由该节点向其他节点分发证书及配置
该节点同时作为 CA
生成 CA- kubeadm init phase certs etcd-ca
复制代码 生成如下文件
- /etc/kubernetes/pki/etcd/ca.crt
- /etc/kubernetes/pki/etcd/ca.key
为方便接下来的步调操作,先将 etcd 节点信息导出为环境变量- export HOST0=192.168.1.101
- export HOST1=192.168.1.102
- export HOST2=192.168.1.103
- export NAME0="etcd-01"
- export NAME1="etcd-02"
- export NAME2="etcd-03"
复制代码 为 etcd 成员生成 kubeadm 配置- HOSTS=(${HOST0} ${HOST1} ${HOST2})
- NAMES=(${NAME0} ${NAME1} ${NAME2})
- for i in "${!HOSTS[@]}"; do
- HOST=${HOSTS[$i]}
- NAME=${NAMES[$i]}
- mkdir -p /tmp/${HOST}
- cat << EOF > /tmp/${HOST}/kubeadmcfg.yaml
- ---
- apiVersion: "kubeadm.k8s.io/v1beta4"
- kind: InitConfiguration
- nodeRegistration:
- name: ${NAME}
- localAPIEndpoint:
- advertiseAddress: ${HOST}
- ---
- apiVersion: "kubeadm.k8s.io/v1beta4"
- kind: ClusterConfiguration
- etcd:
- local:
- serverCertSANs:
- - "${HOST}"
- peerCertSANs:
- - "${HOST}"
- extraArgs:
- - name: initial-cluster
- value: ${NAMES[0]}=https://${HOSTS[0]}:2380,${NAMES[1]}=https://${HOSTS[1]}:2380,${NAMES[2]}=https://${HOSTS[2]}:2380
- - name: initial-cluster-state
- value: new
- - name: name
- value: ${NAME}
- - name: listen-peer-urls
- value: https://${HOST}:2380
- - name: listen-client-urls
- value: https://${HOST}:2379
- - name: advertise-client-urls
- value: https://${HOST}:2379
- - name: initial-advertise-peer-urls
- value: https://${HOST}:2380
- EOF
- done
复制代码 为每个成员创建证书- kubeadm init phase certs etcd-server --config=/tmp/${HOST2}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-peer --config=/tmp/${HOST2}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-healthcheck-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
- kubeadm init phase certs apiserver-etcd-client --config=/tmp/${HOST2}/kubeadmcfg.yaml
- cp -R /etc/kubernetes/pki /tmp/${HOST2}/
- # Clear useless cert
- find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete
- kubeadm init phase certs etcd-server --config=/tmp/${HOST1}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-peer --config=/tmp/${HOST1}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-healthcheck-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
- kubeadm init phase certs apiserver-etcd-client --config=/tmp/${HOST1}/kubeadmcfg.yaml
- cp -R /etc/kubernetes/pki /tmp/${HOST1}/
- find /etc/kubernetes/pki -not -name ca.crt -not -name ca.key -type f -delete
- kubeadm init phase certs etcd-server --config=/tmp/${HOST0}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-peer --config=/tmp/${HOST0}/kubeadmcfg.yaml
- kubeadm init phase certs etcd-healthcheck-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
- kubeadm init phase certs apiserver-etcd-client --config=/tmp/${HOST0}/kubeadmcfg.yaml
- # Clear ca key from member
- find /tmp/${HOST2} -name ca.key -type f -delete
- find /tmp/${HOST1} -name ca.key -type f -delete
复制代码 将证书移动到对应的成员服务器- scp -r /tmp/${HOST2}/pki root@${HOST2}:/etc/kubernetes/
- scp /tmp/${HOST2}/kubeadmcfg.yaml root@${HOST2}:~/
- scp -r /tmp/${HOST1}/pki root@${HOST1}:/etc/kubernetes/
- scp /tmp/${HOST1}/kubeadmcfg.yaml root@${HOST1}:~/
- mv /tmp/${HOST0}/kubeadmcfg.yaml ~/
- rm -rf /tmp/${HOST2}
- rm -rf /tmp/${HOST1}
- rm -rf /tmp/${HOST0}
复制代码 此时在三台 etcd 节点中的文件结构均应如下- /root
- └── kubeadmcfg.yaml
- ---
- /etc/kubernetes/pki
- ├── apiserver-etcd-client.crt
- ├── apiserver-etcd-client.key
- └── etcd
- ├── ca.crt
- ├── ca.key # 仅 CA 节点既 etcd-01
- ├── healthcheck-client.crt
- ├── healthcheck-client.key
- ├── peer.crt
- ├── peer.key
- ├── server.crt
- └── server.key
复制代码 创建静态 Pod 清单
说明
全部 etcd 节点
- kubeadm init phase etcd local --config=/root/kubeadmcfg.yaml
复制代码 检查集群运行情况
将 ${HOST0} 替换为想要检查的节点 ip- ETCDCTL_API=3 etcdctl \
- --cert /etc/kubernetes/pki/etcd/peer.crt \
- --key /etc/kubernetes/pki/etcd/peer.key \
- --cacert /etc/kubernetes/pki/etcd/ca.crt \
- --endpoints https://${HOST0}:2379 endpoint health
复制代码 使用 kubeadm 创建高可用集群
说明
配置过程中需要完全重置控制平面节点的配置时,需要有至少一台能够访问集群的节点,在该节点上按如下游程操作- kubectl delete pods,nodes,namespaces,deployments,services --all --all-namespaces --force
- kubectl delete -f tigera-operator.yaml --force
- kubectl delete -f custom-resources.yaml --force
- kubeadm reset --cleanup-tmp-dir -f
- rm -rf /etc/cni/net.d/*
- rm -rf ~/.kube
- systemctl restart kubelet containerd
复制代码 为 kube-apiserver 创建负载平衡
说明
本文中负载平衡使用 Nginx
Nginx 配置- http {
- ...
- }
- stream {
- upstream apiserver {
- server 192.168.1.104:6443 weight=5 max_fails=3 fail_timeout=30s; # Master-01
- server 192.168.1.105:6443 weight=5 max_fails=3 fail_timeout=30s; # Master-02
- server 192.168.1.106:6443 weight=5 max_fails=3 fail_timeout=30s; # Master-03
- }
- server {
- listen 8443;
- proxy_pass apiserver;
- }
- }
复制代码 为控制平面节点配置外部 etcd 节点
说明
任一 etcd 节点与主控制平面节点,本文中为 Etcd-01 与 Master-01
从集群中任一 etcd 节点复制到主控制平面节点- scp /etc/kubernetes/pki/etcd/ca.crt /etc/kubernetes/pki/apiserver-etcd-client.crt /etc/kubernetes/pki/apiserver-etcd-client.key root@192.168.1.104:~
复制代码 在主控制平面节点中将文件移动到指定位置- mkdir -p /etc/kubernetes/pki/etcd
- mv ~/ca.crt /etc/kubernetes/pki/etcd/
- mv ~/apiserver-etcd-client.crt /etc/kubernetes/pki/
- mv ~/apiserver-etcd-client.key /etc/kubernetes/pki/
复制代码 创建 kubeadm-config.yaml,内容如下
- controlPlaneEndpoint: 负载平衡服务器
- etcd
- networking
- ---
- apiVersion: kubeadm.k8s.io/v1beta4
- kind: ClusterConfiguration
- kubernetesVersion: v1.32.0
- controlPlaneEndpoint: 192.168.1.100:8443
- etcd:
- external:
- endpoints:
- - https://192.168.1.101:2379
- - https://192.168.1.102:2379
- - https://192.168.1.103:2379
- caFile: /etc/kubernetes/pki/etcd/ca.crt
- certFile: /etc/kubernetes/pki/apiserver-etcd-client.crt
- keyFile: /etc/kubernetes/pki/apiserver-etcd-client.key
- networking:
- dnsDomain: cluster.local
- podSubnet: 10.244.0.0/24
- serviceSubnet: 10.96.0.0/16
复制代码 初始化主控制平面
说明
主控制平面节点,本文中为 Master-01
- --upload-certs: 将控制平面间的共享证书上传到 kubeadm-certs Secret
- kubeadm-certs Secret 和解密密钥将在两小时后失效
- 如果要重新上传证书并生成新的解密密钥,需要在已参加集群的控制平面节点上执行 kubeadm init phase upload-certs --upload-certs
- kubeadm init --config kubeadm-config.yaml --upload-certs
复制代码 期待运行完成后应输出雷同如下内容- ...
- Your Kubernetes control-plane has initialized successfully!
- To start using your cluster, you need to run the following as a regular user:
- mkdir -p $HOME/.kube
- sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
- sudo chown $(id -u):$(id -g) $HOME/.kube/config
- Alternatively, if you are the root user, you can run:
- export KUBECONFIG=/etc/kubernetes/admin.conf
- You should now deploy a pod network to the cluster.
- Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
- https://kubernetes.io/docs/concepts/cluster-administration/addons/
- You can now join any number of control-plane nodes running the following command on each as root:
- kubeadm join 192.168.1.100:8443 --token 7r34LU.iLiRgu2qHdAeeanS --discovery-token-ca-cert-hash sha256:9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08 --control-plane --certificate-key 03d66dd08835c1ca3f128cceacd1f31ac94163096b20f445ae84285bc0832d72
- Please note that the certificate-key gives access to cluster sensitive data, keep it secret!
- As a safeguard, uploaded-certs will be deleted in two hours; If necessary, you can use
- "kubeadm init phase upload-certs --upload-certs" to reload certs afterward.
- Then you can join any number of worker nodes by running the following on each as root:
- kubeadm join 192.168.1.100:8443 --token 7r34LU.iLiRgu2qHdAeeanS --discovery-token-ca-cert-hash sha256:9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08
复制代码 先将控制台输出的以上内容生存,稍后将使用这些命令来将其他控制平面节点和工作节点参加集群
根据输出的提示,复制 kubeconfig 用于 kubectl- mkdir -p ~/.kube
- cp /etc/kubernetes/admin.conf ~/.kube/config
复制代码 应用 CNI 插件
由于该清单过大,kubectl apply 会产生如下报错,使用 kubectl create 或 kubectl replace
注意
确认 custom-resources.yaml 中 calicoNetwork 配置的 ip cidr 与集群 podSubnet 配置一致
- # kubectl apply -f https://raw.githubusercontent.com/projectcalico/calico/refs/heads/release-v3.29/manifests/tigera-operator.yaml
- # The CustomResourceDefinition "installations.operator.tigera.io" is invalid: metadata.annotations: Too long: may not be more than 262144 bytes
- wget https://raw.githubusercontent.com/projectcalico/calico/refs/heads/release-v3.29/manifests/tigera-operator.yaml
- wget https://raw.githubusercontent.com/projectcalico/calico/refs/heads/release-v3.29/manifests/custom-resources.yaml
- kubectl create -f tigera-operator.yaml
- kubectl create -f custom-resources.yaml
复制代码 输入以下内容查看控制平面组件 pod 启动状态初始化其他控制平面
说明
除主控制平面节点外的其他控制平面节点,本文中为 Master-02 Master-03
使用 kubeadm join 命令参加集群的节点会将 KubeConfig 同步到 /etc/kubernetes/admin.conf
依照上面输出的命令,分别在其他控制平面节点中执行
- --control-plane: 通知 kubeadm join 创建一个新控制平面
- --certificate-key xxx: 从集群 kubeadm-certs Secret 下载控制平面证书并使用给定的密钥解密
- kubeadm join 192.168.1.100:8443 --token 7r34LU.iLiRgu2qHdAeeanS --discovery-token-ca-cert-hash sha256:9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08 --control-plane --certificate-key 03d66dd08835c1ca3f128cceacd1f31ac94163096b20f445ae84285bc0832d72
复制代码 根据输出的提示,复制 kubeconfig 用于 kubectl- mkdir -p ~/.kube
- cp /etc/kubernetes/admin.conf ~/.kube/config
复制代码 初始化负载节点
说明
全部负载节点
使用 kubeadm join 命令参加集群的节点会将 KubeConfig 同步到 /etc/kubernetes/kubelet.conf
依照上面输出的命令,分别在负载节点中执行- kubeadm join 192.168.1.100:8443 --token 7r34LU.iLiRgu2qHdAeeanS --discovery-token-ca-cert-hash sha256:9f86d081884c7d659a2feaa0c55ad015a3bf4f1b2b0b822cd15d6c15b0f00a08
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